OIDC login, passkeys, and API-key OAuth2 (callback vs device).
Browser SSO into FeatherPanel. Not the same as [API-key OAuth2](../api/oauth2.md).
WebAuthn login and account credentials (Touch ID, Windows Hello, security keys).
Callback mode=user|server and device flow for fp_ API keys.
Build callback URLs and try the device poll flow against a live panel.